title: Delayed time-point 18F-FDG PET CT imaging enhances assessment of atherosclerotic plaque inflammation.
abstract: OBJECTIVE
  The aim of this study was to determine the ideal circulation time of fluorine-18 fluorodeoxyglucose (F-FDG) in order to detect and quantify atherosclerotic plaque inflammation with PET computed tomography (CT) imaging.
  
  
  METHODS
  Fifteen patients underwent multiple time-point imaging at ∼60, 120, and 180 min after F-FDG administration. For each time point, global assessment of aortic and carotid F-FDG uptake was determined qualitatively by visual assessment and semiquantitatively by calculation of the mean and maximum standardized uptake values (SUV) and the corresponding target-to-background ratio (TBR).
  
  
  RESULTS
  Delayed imaging achieved significant improvement in visualization of atherosclerotic plaque inflammation [Friedman's χ statistic (d.f.=2, n=15)=24.13, P<0.001, Kendall's W=0.80]. This observation was confirmed by semiquantitative image analysis. At 1 h, the aortic and carotid SUVmean-calculated TBR was 1.05 [95% confidence interval (CI)=0.98, 1.11] and 0.88 (95% CI=0.81, 0.96), respectively. At 3 h, the TBR significantly increased to 1.57 (95% CI=1.28, 1.86; P=0.001) for the aorta and to 1.61 (95% CI=1.36, 1.87; P<0.001) for the carotid arteries. SUVmax-calculated TBRs showed a similar increase over time.
  
  
  CONCLUSIONS
  One- and 2-h F-FDG PET CT imaging is suboptimal for global assessment of atherosclerotic plaque inflammation compared with imaging at 3 h. Our data support the utilization of 3-h delayed imaging to obtain optimal data for the detection and quantification of atherosclerotic plaque inflammation in human arteries.
authors.affiliation: Perelman School of Medicine at the University of Pennsylvania, USA.
authors.forename: Björn A
authors.initials: BA
authors.lastname: Blomberg
authors.forename: Scott R
authors.initials: SR
authors.lastname: Akers
authors.forename: Babak
authors.initials: B
authors.lastname: Saboury
authors.forename: Nehal N
authors.initials: NN
authors.lastname: Mehta
authors.forename: Gang
authors.initials: G
authors.lastname: Cheng
authors.forename: Drew A
authors.initials: DA
authors.lastname: Torigian
authors.forename: Esther
authors.initials: E
authors.lastname: Lim
authors.forename: Catherine
authors.initials: C
authors.lastname: Del Bello
authors.forename: Thomas J
authors.initials: TJ
authors.lastname: Werner
authors.forename: Abass
authors.initials: A
authors.lastname: Alavi
mesh_terms: D001692:Biological Transport; D015331:Cohort Studies; D005260:Female; D019788:Fluorodeoxyglucose F18 / Q000378:metabolism; D006801:Humans; D007249:Inflammation / Q000000981:diagnostic imaging / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D064847:Multimodal Imaging / Q000379:methods*; D058226:Plaque, Atherosclerotic / Q000000981:diagnostic imaging* / Q000378:metabolism; D049268:Positron-Emission Tomography / Q000379:methods*; D013997:Time Factors; D014057:Tomography, X-Ray Computed / Q000379:methods*
chemical_list: D019788:Fluorodeoxyglucose F18